Identification marks are used for identification of people or objects in many fields of daily life. According to the prior art, identification marks based on barcodes are used, although these are labor-intensive and thus expensive in use, since they must be read using a complex optical read apparatus.
One alternative to barcode systems is “Radio Frequency Identification Tags” (RFID Tags). An RFID tag normally contains an antenna, a circuit for reception and transmission of electromagnetic waves (transponder) and a signal processing circuit. An RFID tag such as this is thus frequently formed on a small silicon chip, which is connected to an antenna that is applied to a plastic mount.
An RFID tag makes it possible to read and store data without making any contact. Data such as this is stored on RFID tags (clearly electronic labels). The stored data is read by means of electromagnetic waves which can be injected into the RFID tag via the antenna.
Fields of operation for an RFID tag are electronic security systems for theft prevention, applications in automation (for example the automatic identification of vehicles in the traffic for toll payment systems), access monitoring systems, cashless payment, ski passes, fuel cards, animal identification and applications in logistics.
RFID tags are thus small transponders which can be read by radio and are formed from a memory chip and an antenna. A unique electronic product code (EPC) can also be stored in the memory chip and may possibly replace the conventional thirteen-digit EAN barcode (“European Article Number”) that is now in commercial use. Each individual product can be provided with a unique number throughout the world, by means of the EPC code. The memory chip can also store certain amounts of data—directly on the object—which can be called up at any time, without any connection to a database.
Many German and foreign companies from the retail sector are planning to use RFID technologies in the supplier area. The volume of investment just in the USA up to the year 2008 is estimated to be $1.3 million US dollars (see [1]).
However, modern available RFID transponders have very small memory capacitors, so that only a small number of bytes of information can frequently be stored. Information comprising a plurality of kilobytes can thus not be stored with such known RFID tags. The aim in an RFID system for example in an RFID aided automatic inventory system, is to store relatively large amounts of data directly at the object and thus at the transponder (“Data on Tag”, DOT), and this is often not feasible, while maintaining full function, with modern commercially-available transponders owing to the small available memory capacity. One field of application in which such large amounts of data occur is the storage of maintenance data for a technical installation or machine, or for a relatively high-value item on an RFID tag.
A schematically illustrated identification data-storage medium 100 according to the prior art will be described in the following text with reference to FIG. 1.
The identification data-storage medium 100 (that is to say an RFID tag) contains a memory device 102 in which data for a specific amount of storage, for example 8 bytes, can be stored. If the aim is to store data for a data model 101 (that is to say data containing information) in the memory 102 of the transponder 100, then, if the data model 101 is too large, this amount of data no longer fits as an entity into the memory device 102 for the RFID tag 100.
According to the prior art, the amounts of data are thus either cut down and/or are stored in compressed form on the transponder owing to the restricted memory capacity of the RFID transponders, to such an extent that only the absolutely necessary data is stored. In the extreme, this can even lead in some cases to only the UID (“Unique Identifier”) of the RFID transponder being stored as an identification feature in the memory area of the RFID. Additional object data is then taken from an external database. However, this results in the actual major advantage of RFID tags being lost, this being that the data is all available directly in the transponder, and thus directly at the object.